Lamp



H. A. DOUGLAS.

LAMP.

APPLICATION FILED MAR. 13, I919.

Patented May 10, 1921.

erence to the accompanying drawing showum're STATES,

PT-ENT OFFICE.

HARRY A. DOUGLAS, 0]? BRONSOIN', MICHIGAN.

LAMP.

which the following is a full,-clear, concise,

and exact description.

My invention relates to the mounting of incandescent lamps and also to mechanism for controlling the position thereof with respect to their mountings or holders. The device of my invention is of particular utility when employed in reflecting lamps such as that used as'headlights for automobiles. v

I will explain my invention fully by refing the preferred embodiment thereof and in which Figure 1 illustrates a holder and complemental parts which are adapted for incor oration in a reflecting lamp structure; ig. 2 is a view of the structure shown in Fig. 1 taken at right angles to the direction in which Fig. 1 is taken and showing the structure of Fig. 1 assembled with elements of a reflecting lamp; Fig. 3 is a sectional view on line 33 of Fig. 2, parts being shown in full elevation; Fig. 4 is a sectional view on'line 44 of Fig. 3; and Fig. 5 is a sectional view on line 55 of Fig. 2.

Like parts are indicated by similar characters of reference throughout the different figures.

In Fig. 2 I have illustrated the casing 1 of a' reflecting lamp, this casing surrounding a reflector 2 as will be well understood by those skilled in the art. A cylindrical holder 3 is shown as being on the axis of the lam this holder being secured at the rear of t e reflector and projecting rearwardly of the reflector. A cylindrical shell 4 is within the holder 3 and is movable longitudinally thereof wherebythe incandescent lamp 5 at the forward end of the shell may be focused with respect to the reflector before which it is disposed. The base of the lamp is provided with the usual bayonet pins 6 receivable in the bayonet slots 7 at the forward end of the shell. The structure illustrated is a single pole structure to which however the invention is not to be limited.

The lamp being a single pole lamp, has a central contact 8 on the inner end of its base, the base being surrounded by a me- Speciflcation of Letters Patent.

crent. One terminal of the lamp filament 9 Patented May 10, 1921.

Application filed March 13, 1919. Serial No. 282,451.

tallic sheath which is connected with the metallic shell 4 that is grounded 'or otherwise suitably connected with the source of ouris connected withthe contact 8 and the other terminal of the lamp filament is connected with the aforesaid metallic sheath. The plug or contact carrier 10 by which the in candescent lamp is to be included in circuit is received in the outer or rear end of the shell 4 and is assembled with such shell by any suitable means such as the outwardly spring pressed pins 11 receivable in the circular holes 12 in accordance with the construction forming the subject matter of my co-pendlng application Serial No. 282,450 filed March 13, 1919.

As set forth in said co-pending application, one of these pins is longer than the other and projects into an elongated slot 3 1n the holder 3 whereby one of these pins takes part in assembling the shell and holder.

A pin 13 supplements the longer pin 11 preventing undesired relative motion between the holder 3 and shell 4. In the form of the invention illustrated this pin is received in a channel 14 formed in and extending longitudinally of the holder 3 whereby relative rotary movement between the holder and shell is prevented although relative longitudinal movement between the shell and holder is permitted in order that the lamp may be focused. Where the plug 10 is not directly accessible for the purpose of effecting its movement and thereby the movement of the shell with which it is coupled, I provide said plug with a stem 15 that is rearwardly extended to be operable from the exterior of the lamp casing 1, this stem including the pin as a part of its formation, on which account thestem is alined with the channel 14 in the holder 3. In assembling the parts the lamp 5 may be initially omitted to permit such a rearward positioning of the shell 4 as to permit the pin 13 to be slidabl inserted in the engaging hole 13' in the s ell while this hole is at the rear of the holder 3, whereafterthe shell 4 may be moved forwardly to bring the pin and the stem in the channel 14. This channel is covered or overhung by a portion of the holder or a portion carried by the holder 3 is fixed with respect to the reflector 2, it holds the stem 15 from rotation as well as holding the shell tfrom rotation. This enables me to employ an adjusting nut 16 at the rear end of the casing 1 in which the adjusting nut is rotatable and as this nut is in threaded engagement with a non-rotatable stem, the stem is forced to move in or out upon the rotation of the nut, whereby the plug and shell and the lamp assembled with the shell are moved in and out, the channel 14 being sufliciently long to accommodate the inner end of the stem 15 throughout the range of movement which the stem has in order to place the lamp 5 in any desired position.

The nut 16 is desirably of two-part formation. The part of the nut which is in direct threaded engagement with the stem is at the body portion of a spider 17 whose legs 18 are of spring formation adapted to be contracted or collapsed together sufliciently to be passed from the exterior of the casing. After passing through this opening" the spider legs spread apart and have spring engagement with the inner face of the casing 1. The other part 20 of the nut has its headupon the exterior of the casing and its neck 21 journaled in the circular opening 19. Tongues 22 are formed upon the part 20 and pass between the legs 18 of the spider. These tongues are turned inwardly at their inner ends. These inner ends constitute an abutment which engages and positions the body portion of the spider l7 and forces the spider legs 18 to have spring engagement with the casing 1. In this way the two parts 17 and 20 of the nut are assembled with the casing. The nut portion 20 may be turned in either direction to impart a corresponding movement to the spider and thereby to cause the consequent inward or outward movement of the stem 15 with the results which have been described.

IVhile I have herein shown and particularly described the preferred embodiment of my invention I do not wish to be limited to the precise details of construction shown as changes may readily be made without departing from the spirit of my invention, but having thus described my invention I claim as new and desire to secure by Letters Patent the following 1. A lamp structure including an incaninto said channel; and a stem extending 4 rearwardly through said channel and carrying said pin.

2. A lamp structure including an incandescent lamp; a shell carrying the lamp at one of its ends; a contact carrying plug at the other end of the shell for including the lamp in circuit; a holder receiving the shell and along which the shell is movable, said holder having a channel extending longitudinally of the holder, this channel being overhung by a portion upon the holder; a reflector from which the holder rearwardly extends and before which the lamp is disposed; a pin slidably entering the shell and projecting into said channel; a stem extending rearwardly through said channel and carrying said pin; a casing for the lamp; and a nut in threaded engagement with the stem and accessible for operation from the rear of the casing.

3. A reflecting lamp including a reflector; an incandescent lamp disposed in front of the reflector; a shell in which the lamp is mounted; a stem coupled with the shell; a casing; and a two-part nut in threaded engagement with the stem, the portion of the nut in direct engagement with the stem being of spring leg spider formation and the portion of the nut which is accessible for operation having tongue formation passing between the legs of the spider and engaging the body of the spider.

4. A reflecting lamp including a reflector; an incandescent lamp disposed in front of the reflector; a shell in which the lamp is mounted; a stem coupled with the shell; a casing; and a nut in threaded engagement with the stem and having a collapsible spring portion engageable with the interior of the casing and a head engageable with the exterior of the casing.

In witness whereof, I hereunto subscribe my name this 4th day of March A. D., 1919.

HARRY A. DOUGLAS. 

